Updating a Column to NULL

Use the NULL keyword to modify a column value when you use the UPDATE statement. For example, for a customer whose previous address required two address lines but now requires only one, you would use the following entry:

UPDATE customer
   SET address1 = '123 New Street',
   SET address2 = null,
   city = 'Palo Alto',
   zipcode = '94303'
   WHERE customer_num = 134;